Electro-optical device comprising an anisotropic conductive film having a plurality of electrically conductive particles arranged differently than a plurality of recessed portions of a terminal and electronic apparatus

ABSTRACT

An electro-optical device includes: a liquid crystal panel; a particle aligned type anisotropic conductive film having a plurality of electrically conductive particles that are arranged in a state of being aligned along a first direction and a second direction intersecting with the first direction; and a printed circuit board coupled to a connection terminal portion of the liquid crystal panel via the particle aligned type anisotropic conductive film, wherein the connection terminal portion includes a plurality of connection terminals, a plurality of recessed portions that are arranged in a state of being aligned along a third direction and a fourth direction intersecting with the third direction are formed on a surface of the connection terminal, and at least one of the first direction and the second direction along which the electrically conductive particles are arranged is different in arrangement direction from both the third direction and the fourth direction.

The present application is based on, and claims priority from JPApplication Serial Number 2020-142423, filed Aug. 26, 2020, thedisclosure of which is hereby incorporated by reference herein in itsentirety.

BACKGROUND 1. Technical Field

The present disclosure relates to an electro-optical device and anelectronic apparatus.

2. Related Art

As the electro-optical device, there has been known an active drive typeliquid crystal device that includes switching elements each provided foreach pixel. For example, such a liquid crystal device is used as a lightvalve of a projector as an electronic apparatus.

The liquid crystal device includes a liquid crystal panel having adisplay region in which a plurality of pixels are arranged. A flexiblewiring substrate (flexible printed circuit: FPC) is coupled toconnection terminals of the liquid crystal panel via an anisotropicconductive film (ACF). A drive signal and a drive voltage are suppliedto the liquid crystal panel through the flexible wiring substrate.

Recently, along with the miniaturization and a demand for highdefinition of a liquid crystal device and other electronic apparatus, anattempt to make a pitch of connection terminals fine has been inprogress, and an anisotropic conductive film is also requested to followsuch an attempt to make the pitch fine.

However, when electrically conductive particles are filled in theanisotropic conductive film at high density in order to ensure theelectrical conduction also in a narrow space between connectionterminals in a state where the electrically conductive particles aresandwiched between the connection terminals with certainty, a rate ofoccurrence of short circuiting between terminals is increased since theelectrically conductive particles dispersed between the connectionterminals are continuously arranged.

In view of such circumstances, there has been developed an anisotropicconductive film capable of preventing the occurrence of short circuitingbetween the terminals that is caused by such continuously arrangedelectrically conductive particles in a space between the connectionterminals that are disposed at a fine pitch. As an anisotropicconductive film adaptable to such a fine pitch, for example,JP-A-2020-38993 discloses an anisotropic conductive film in whichelectrically conductive particles are regularly arranged in a state ofbeing aligned in a predetermined arrangement pattern (hereinafter,referred to as a particle aligned type anisotropic conductive film).

Further, there has been known that a plurality of recessed portions areformed on a surface of the connection terminal. This is because, at theconnection terminal, recesses are generated in the connection structurebetween an electrode layer that is brought into contact with theconductive particles and a wiring layer below the electrode layer. Theprocess of forming the recessed portions is described in detail later.

However, when a panel size is miniaturized without changing theresolution of the liquid crystal panel or when the resolution isincreased without changing the panel size, it is necessary to optimizesizes such as a width and a length and a connection terminal pitch ofconnection terminals for connection with an external printed circuitboard such as a flexible wiring substrate corresponding to narrowing ofa connection terminal region brought about by the miniaturization of thepanel size and the increase of the number of connection terminalsbrought about by higher resolution. When a particle aligned anisotropicconductive film is used, there is a drawback that, among the pluralityof arranged connection terminals, there appears a connection terminalwhere a large number of electrically conductive particles fall intorecessed portions so that a pressing force is not properly applied tothe electrically conductive particles at the time of performingcompression bonding of the flexible wiring substrate whereby theelectrically conductive particles are not collapsed properly thusdeteriorating the electrical connection performance.

SUMMARY

An electro-optical device includes: an electro-optical panel, ananisotropic conductive film having a plurality of electricallyconductive particles that are arranged in a state of being aligned alonga first direction and a second direction intersecting with the firstdirection as viewed in plan view; and a printed circuit board coupled toa connection terminal portion of the electro-optical panel via theanisotropic conductive film, wherein the connection terminal portionincludes a plurality of terminals, a plurality of recessed portions thatare arranged in a state of being aligned along a third direction and afourth direction intersecting with the third direction are formed on asurface of each terminal, and at least one of the arrangement directionsof the electrically conductive particles along the first direction andthe second direction differs from both arrangement directions of therecessed portions along the third direction and the fourth direction.

An electronic apparatus includes the electro-optical device describedabove.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a configuration of a liquidcrystal device.

FIG. 2 is a side view illustrating the configuration of the liquidcrystal device illustrated in FIG. 1.

FIG. 3 is a plan view illustrating a configuration of a connectionterminal portion according to a first embodiment.

FIG. 4 is a plan view for explaining an angle of a first arrangementdirection.

FIG. 5 is a plan view for explaining the angle of the first arrangementdirection.

FIG. 6 is a plan view illustrating the configuration of the connectionterminal portion of the liquid crystal device.

FIG. 7 is a plan view for explaining an angle of a second arrangementdirection.

FIG. 8 is a plan view for explaining the angle of the second arrangementdirection.

FIG. 9 is a plan view illustrating a state of the connection terminalportion after compression bonding.

FIG. 10 is a plan view illustrating a state of the connection terminalportion after compression bonding.

FIG. 11 is a schematic view illustrating a configuration of a projectoras an electronic apparatus.

FIG. 12 is a plan view illustrating a configuration of a connectionterminal portion according to a second embodiment.

FIG. 13 is a plan view illustrating a configuration of a connectionterminal portion according to a third embodiment.

FIG. 14 is a plan view illustrating a configuration of a connectionterminal portion according to another mode of the third embodiment.

FIG. 15 is a plan view illustrating a configuration of a connectionterminal portion according to a first modification example.

FIG. 16 is a plan view illustrating a configuration of a connectionterminal portion according to a second modification example.

FIG. 17 is a plan view illustrating a configuration of a connectionterminal portion according to a third modification example.

FIG. 18 is a plan view illustrating a configuration of a connectionterminal portion according to a fourth modification example.

FIG. 19 is a plan view illustrating a configuration of a connectionterminal portion according to another mode of the fourth modificationexample.

FIG. 20 is a plan view illustrating a configuration of a connectionterminal portion according to a fifth modification example.

FIG. 21 is a plan view illustrating a configuration of a connectionterminal portion according to another mode of the fifth modificationexample.

FIG. 22 is a plan view illustrating a configuration of a connectionterminal portion according to a sixth modification example.

FIG. 23 is a plan view illustrating a configuration of a connectionterminal portion according to another mode of the sixth modificationexample.

FIG. 24 is a plan view illustrating a configuration of a connectionterminal portion according to another mode of the sixth modificationexample.

FIG. 25 is a plan view illustrating a configuration of a knownconnection terminal portion.

FIG. 26 is a cross-sectional view illustrating the configuration of theknown connection terminal portion.

DESCRIPTION OF EXEMPLARY EMBODIMENTS First Embodiment

As illustrated in FIG. 1 and FIG. 2, a liquid crystal device 500 thatforms an electro-optical device includes a liquid crystal panel 100 asan electro-optical panel, and a printed circuit board 110 that iscoupled to one side of the liquid crystal panel 100. Here, in FIG. 1 andFIG. 2, the description of some constitutional elements is omitted whenappropriate provided that such omission of the description does notobstruct the description of the configuration, the manner of operation,and the advantageous effects of the present disclosure. For example, theliquid crystal device 500 is used as a light valve of a projector 1000as an electronic apparatus described later.

Hereinafter, for the sake of convenience of the description, thedescription is made using an X axis, a Y axis, and a Z axis that areorthogonal to each other when necessary. A direction along the X axis isdescribed as an X direction. In the same manner, a direction along the Yaxis is described as a Y direction. A direction along the Z axis isdescribed as a Z direction. Additionally, in the following description,an extending direction of a long side of a connection terminal 50 of aconnection terminal portion 40 is described as a Y direction, and anextending direction of a short side of the connection terminal 50 isdescribed as an X direction, and “viewing the connection terminalportion in a Z direction” is described as “as viewed in plan view”.

The liquid crystal panel 100 includes a plurality of pixels that arearranged in a matrix array in the X direction and the Y direction in adisplay region, and the description of the plurality of pixels isomitted. The liquid crystal panel 100 is an active drive type liquidcrystal panel.

Although not illustrated in the drawings, in respective pixels, a pixelelectrode, a switching element, a counter electrode, a holding capacitorand the like are provided correspondingly. The switching element isconfigured to control switching of the pixel electrode. The counterelectrode faces the pixel electrode via a liquid crystal layer. Thepixel electrodes, the switching elements, and the holding capacitors aremounted on an element substrate 10. For example, the switching elementis a thin film transistor (TFT). The counter electrode is mounted on acounter substrate 20 at least over the display region such that thecounter electrode faces the plurality of pixel electrodes. The pixelelectrodes and the counter electrode are each formed using a transparentconductive film made of indium tin oxide (ITO), indium zinc oxide (IZO)or the like, for example.

A connection terminal portion 40 is disposed on an overhang portion 12of the element substrate 10. The connection terminal portion 40 is aportion where connection terminals 50 a and 50 b (see FIG. 3) that formterminals disposed on the liquid crystal panel 100 and externalterminals 111 a, 111 b (see FIG. 9) formed on the printed circuit board110 are respectively electrically coupled to each other via a particlealigned type anisotropic conductive film (ACF) 70 (see FIG. 3). Forexample, the printed circuit board 110 is a flexible board such as aflexible wiring substrate (flexible printed circuit: FPC). Here, adriving integrated circuit (IC) for driving the liquid crystal panel 100may be mounted on the printed circuit board 110.

As illustrated in FIG. 1 and FIG. 2, a first dustproof substrate 31 isdisposed on an element substrate 10 side of the liquid crystal panel100. A second dustproof substrate 32 is disposed on a counter substrate20 side of the liquid crystal panel 100.

As illustrated in FIG. 3, a connection terminal portion 40 a is mountedon the overhang portion 12 of the element substrate 10 (see FIG. 1 andFIG. 2). The connection terminal portion 40 a has the first connectionterminal 50 a that is one of the connection terminals, and a secondconnection terminal 50 b adjacent to the first connection terminal 50 aand is one of the connection terminals. Typically, a plurality of theconnection terminals 50 a (50 b) are arranged at equal intervals in theX direction, for example. Further, a plurality of recessed portions 51are formed in a lattice shape and at equal intervals along the Xdirection and the Y direction on surfaces of the first connectionterminal 50 a and the second connection terminal 50 b, that is, on anelectrode layer that is configured to contact electrically conductiveparticles 71 attributed to the connection structure between theelectrode layer and a wiring layer below the electrode layer. Asdescribed above, a state where the plurality of recessed portions 51 arearranged in a lattice shape and at equal intervals along the X directionand the Y direction can be paraphrased as a state where the plurality ofrecessed portions 51 are arranged in a state of being aligned. Further,the particle aligned type anisotropic conductive film 70 is adhered tothe first connection terminal 50 a and the second connection terminal 50b. In FIG. 3, the illustration of the printed circuit board 110 isomitted. Here, in the present embodiment, the X direction corresponds tothe third direction, and the Y direction corresponds to the fourthdirection.

The recesses 51 are formed because of the following reasons. Theelectrode layer that is brought into contact with the electricallyconductive particles 71 of the first connection terminal 50 a (secondconnection terminal 50 b) is stacked on the wiring layer disposed belowthe electrode layer via an insulating film. For example, the wiringlayer disposed below the electrode layer is used for lines coupled toelectrodes of holding capacitors of the pixels, and lines for the pixelsand switching elements disposed in a peripheral circuit. In forming theconnection structure, the wiring layer disposed below the electrodelayer is exposed by forming openings in the insulating film using aphoto etching technique. Each opening may have a size of approximatelyseveral μm² in order to ensure the electrical connection between theelectrode layer and the wiring layer with certainty. Next, the electrodelayer made of ITO is formed by sputtering as a film that covers theopenings. A film thickness of the electrode layer is approximately 0.2μm, for example. The electrode layer is formed in the same process whereITO films of the pixel electrodes are formed, for example. Since thefilm thickness of the electrode layer is thin compared to the size ofthe opening, the openings cannot be filled with the electrode layer.Accordingly, the recessed portions 51 are formed on the surface of thefirst connection terminal 50 a (second connection terminal 50 b), thatis, on the electrode layer configured to contact the electricallyconductive particle 71. Further, to provide a large number of connectionstructures in order to ensure the electrical connection with certainty,the plurality of recessed portions 51 are formed.

Further, the reason for forming the recessed portions 51 is not limitedto the provision of the connection structure between the electrode layerthat is configured to contact the electrically conductive particles 71and the wiring layer that is disposed below the electrode layer. Forexample, there is a case where two wiring layers are disposed below theelectrode layer configured to contact the electrically conductiveparticles 71, and the connection structure between these two wiringlayers is formed by the formation of the recessed portions. In thiscase, when an insulating layer above the wiring layers is removed andthe electrode layer configured to contact the electrically conductiveparticles 71 is formed, there may be a case where the recessed portions51 are formed so as to reflect the recessed portions of the connectionstructure.

With respect to the formation of the connection structure, there is amethod that forms a plug structure where small openings are formed and afilm made of tungsten is formed on and filled in the openings bysputtering and, then, a surface of the structural body is flattened.However, the method has a drawback that a manufacturing cost isincreased due to the addition of a tungsten sputtering step and apolishing step.

In the first connection terminal 50 a, a length of a long side 50Lextending along the Y direction is 500 μm, for example, and a length ofa short side 50 s extending along the X direction is 30 μm, for example.The number of first connection terminals 50 a is 200, for example. Apitch between the recessed portion 51 and the recessed portion 51 isapproximately 10 μm in both directions of the X direction and the Ydirection, for example. In the first connection terminal 50 a, adistance from the short side 50S to the recessed portion 51 is 4 μm, forexample. A size of each recessed portion 51 is 2 μm×2 μm, for example. Agap between the first connection terminal 50 a and the second connectionterminal 50 b is 15 μm, for example. In this embodiment, the size of thefirst connection terminal 50 a and the size of the second connectionterminal 50 b are equal.

The electrically conductive particles 71 of the particle aligned typeanisotropic conductive film 70 are regularly arranged in a predeterminedarrangement pattern as viewed in plan view. For example, as illustratedin FIG. 3, the electrically conductive particles 71 are arranged in alattice shape and at equal intervals along a column direction (firstarrangement direction) and a row direction (second arrangementdirection). A state where the plurality of electrically conductiveparticles 71 are arranged in a lattice shape and at equal intervalsalong the first arrangement direction and the second arrangementdirection in this manner can be also referred to as a state where theplurality of electrically conductive particles 71 are arranged in astate of being aligned. In the present embodiment, the first arrangementdirection corresponds to the first direction, and the second arrangementdirection corresponds to the second direction.

In an example illustrated in FIG. 3, the first arrangement directionindicating the arrangement direction of the electrically conductiveparticles 71 of the particle aligned type anisotropic conductive film 70in the column direction intersects with the long side 50L of the firstconnection terminal 50 a, and the electrically conductive particles 71are arranged in a regular arrangement pattern so as to be aligned alongthe first arrangement direction. Here, the second arrangement directionindicating the arrangement direction of the electrically conductiveparticles 71 of the particle aligned type anisotropic conductive film 70in the row direction is not inclined with respect to the short side 50Sof the first connection terminal 50 a, and the electrically conductiveparticles 71 are arranged parallel to the short side 50S of the firstconnection terminal 50 a along the second arrangement direction. Thatis, the first arrangement direction along which the electricallyconductive particles 71 are arranged and the Y direction along which therecessed portions 51 are arranged are different from each other, andthese directions intersect with each other. The arrangement pitch of theelectrically conductive particles 71 is 10 μm, for example. A diameterof each electrically conductive particle 71 is 3 μm, for example.

For example, the electrically conductive particles 71 are each formed ofa core material, a metal coating covering the core material, and aninsulating resin layer covering the metal coating. Since theelectrically conductive particles 71 are each formed by being coatedwith the insulating resin layer, even when the electrically conductiveparticles 71 are arranged at a fine pitch, a short circuiting due toaggregation of the electrically conductive particles 71 minimallyoccurs. However, for enabling the electrical connection, it is necessaryto break the insulating resin film by applying proper pressing to theelectrically conductive particles 71. Accordingly, when there is thedifference among gaps between the connection terminals 50 a (50 b) andthe external terminals of the printed circuit board 110, with respect tothe electrically conductive particles 71 arranged at a wide gap area, asufficient pressing is not applied to the electrically conductiveparticles 71 so that the electrically conductive particles 71 cannotbreak the insulating resin film whereby an electrical connection failureis likely to occur (see FIG. 26). When an excessive pressing force isapplied, the electrically conductive particles 71 at a narrow gap areaare excessively collapsed and lose elasticity. As a result, thereliability of the electrical connection is impaired. In view of theabove, a configuration for decreasing the number of electricallyconductive particles 71 falling into the recessed portions 51 isrequired (see FIG. 25).

Accordingly, by arranging the recessed portions 51 and the electricallyconductive particles 71 as described above, it is possible to suppressthe falling of the large number of electrically conductive particles 71into the recessed portions 51. In addition, the same goes also for thefirst connection terminal 50 a and the second connection terminal 50 badjacent to each other. Accordingly, when the printed circuit board 110is adhered to the connection terminal portion 40 a via the particlealigned type anisotropic conductive film 70 by compression bonding, itis possible to suppress the falling of the large number of electricallyconductive particles 71 into the recessed portions 51. Therefore, it ispossible to suppress the lowering of the electrical connectionperformance of the connection terminal portion 40 a brought about by theinsufficient pressing to the electrically conductive particles 71.

FIG. 4 and FIG. 5 are views for explaining a preferred angle of thefirst arrangement direction. As illustrated in FIG. 4, an angle made byintersection of the Y direction along which the recessed portions 51 arearranged along the long side 50L of the first connection terminal 50 aand the first arrangement direction along which the electricallyconductive particles 71 are arranged is assumed as θ1. A length betweenthe recessed portions 51 at both ends of the long side 50L of the firstconnection terminal 50 a, that is, a length from the recessed portion 51a disposed at an outermost end on one end side of the long side 50L tothe recessed portion 51 b disposed at an outermost end on the other endside of the long side 50L in the same column as the recessed portion 51a is assumed as L. A width of the recessed portion 51 (including therecessed portions 51 a, 51 b) is assumed as D2. In this case, the angleθ1 may be set to satisfy the following formula 1.Tan θ1≥0.5×D2/L  (formula 1)

By disposing the recessed portions 51 and the electrically conductiveparticles 71 so as to satisfy the above-mentioned condition, in acertain column of the electrically conductive particles 71, at least oneelectrically conductive particle 71 can be prevented from falling intothe recessed portion 51 (including the recessed portion 51 a, 51 b) andhence, proper pressing can be applied to the electrically conductiveparticles 71. Accordingly, the first connection terminal 50 a and theprinted circuit board 110 can be electrically coupled to each other.

In FIG. 4, although the formula 1 is proposed on the premise that theelectrically conductive particle 71 agrees with the recessed portion 51a in position, in an actual configuration, there may be a case where theelectrically conductive particle 71 does not agree with the recessedportion 51 a in position. For example, when the conductive particle 71is displaced leftward with respect to the recessed portion 51 a by0.25×D2, there is a risk that the conductive particles 71 are mostlyfall into the recessed portions 51 respectively in the whole region fromthe recessed portion 51 a to the recessed portion 51 b. Taking such acase into consideration, it is preferable to set the angle θ1 so as tosatisfy the relationship of Tan θ1≥D2/L by expanding the formula 1. Insuch a manner, at least one electrically conductive particle 71 can beprevented from falling into the recessed portion 51 (including therecessed portion 51 a, 51 b) and hence, proper pressing can be appliedto the electrically conductive particles 71.

Further, as illustrated in FIG. 5, an angle made by intersection of theY direction along which the recessed portions 51 are arranged along thelong side 50L of the first connection terminal 50 a and the firstarrangement direction along which the electrically conductive particles71 are arranged is assumed as θ2. A length from the recessed portion 51a on one end of the long side 50L of the first connection terminal 50 ato the recessed portion 51 b on the other end of the long side 50L ofthe first connection portion 50 a is assumed as L. An average diameterof the conductive particles 71 is assumed as D1. The width of therecessed portions 51 (including the recessed portions 51 a, 51 b) isassumed as D2. In this case, the angle θ2 may be set to satisfy thefollowing formula 2.Tan θ2≥0.5×(D1+D2)/L  (formula 2)

By disposing the recessed portions 51 (including the recessed portions51 a, 51 b) and the electrically conductive particles 71 so as tosatisfy the above-mentioned condition, in a certain column of theelectrically conductive particles 71, the plurality of electricallyconductive particles 71 can be prevented from falling into the recessedportions 51 (including the recessed portions 51 a, 51 b) and hence,proper pressing can be applied to the electrically conductive particles71. Accordingly, the first connection terminal 50 a and the printedcircuit board 110 can be electrically coupled to each other in a morestable manner.

In the example illustrated in FIG. 6, the first arrangement directionindicating the arrangement direction of the electrically conductiveparticles 71 of the particle aligned type anisotropic conductive film 70in the column direction is equal to the extending direction of the longside 50L of the first connection terminal 50 a, and the electricallyconductive particles 71 are arranged parallel to the direction along thelong side 50L of the first connection terminal 50 a, that is, the Ydirection without inclination. On the other hand, the second arrangementdirection indicating the arrangement direction of the electricallyconductive particles 71 of the particle aligned type anisotropicconductive film 70 in the row direction differs from the extendingdirection of the short side 50S of the first connection terminal 50 a,and the electrically conductive particles 71 are regularly arrangedalong the second arrangement direction. That is, the second arrangementdirection along which the electrically conductive particles 71 arearranged and the X direction along which the recessed portions 51 arearranged differ from each other and intersect with each other.

By arranging the recessed portions 51 and the electrically conductiveparticles 71 as described above, it is possible to suppress the fallingof the large number of electrically conductive particles into therecessed portions 51. In addition, the same goes also for the firstconnection terminal 50 a and the second connection terminal 50 badjacent to each other. Accordingly, when the printed circuit board 110is adhered to the connection terminal portion 40 b via the particlealigned type anisotropic conductive film 70 by compression bonding, itis possible to suppress the falling of the large number of electricallyconductive particles 71 into the recessed portions 51. Therefore, it ispossible to suppress the lowering of the electrical connectionperformance of the connection terminal portion 40 b brought about byinsufficient pressing to the electrically conductive particles 71.

FIG. 7 and FIG. 8 are views for explaining a preferred angle of thesecond arrangement direction in the example illustrated in FIG. 6. Asillustrated in FIG. 7, an angle made by an intersection of the Xdirection along which the recessed portions 51 are arranged along theshort side 50S of the first connection terminal 50 a and the secondarrangement direction along which the electrically conductive particles71 are arranged is assumed as θ3. A length between the recessed portions51 at both ends of the short side 50S of the first connection terminal50 a, that is, a length from the recessed portion 51 a disposed at anoutermost end on one end side of the short side 50S to the recessedportion 51 b disposed at an outermost end on the other end side of theshort side 50S is assumed as W. A width of each recessed portion 51 isassumed as D2. In this case, the angle θ3 may be set to satisfy thefollowing formula 3.Tan θ3≥0.5×D2/W  (formula 3)

By disposing the recessed portions 51 and the electrically conductiveparticles 71 so as to satisfy the above-mentioned condition, in acertain row of the electrically conductive particles 71, at least oneelectrically conductive particle 71 can be prevented from falling intothe recessed portion 51 and hence, proper pressing can be applied to theelectrically conductive particles 71. Accordingly, the first connectionterminal 50 a and the printed circuit board 110 can be electricallycoupled to each other.

Here, in FIG. 7, although the formula 3 is proposed on the premise thatthe electrically conductive particle 71 agrees with the recessed portion51 a in position, in an actual configuration, there may be a case wherethe electrically conductive particle 71 does not agree with the recessedportion 51 a in position. For example, when the conductive particle 71is displaced upward with respect to the recessed portion 51 a by0.25×D2, there is a risk that the conductive particles 71 mostly fallinto the recessed portions 51 respectively in the whole region from therecessed portion 51 a to the recessed portion 51 b. Taking such a caseinto consideration, it is preferable to set the angle θ3 so as tosatisfy the relationship of Tan θ3≥D2/W by expanding the formula 3. Withsuch a configuration, at least one electrically conductive particle 71can be prevented from falling into the recessed portion 51 (includingthe recessed portion 51 a, 51 b) and hence, proper pressing can beapplied to the electrically conductive particles 71.

As illustrated in FIG. 8, an angle made by an intersection of the Xdirection along which the recessed portions 51 are arranged along theshort side 50S of the first connection terminal 50 a and the secondarrangement direction along which the electrically conductive particles71 are arranged is assumed as θ4. A length between the recessed portions51 at both ends of the short side 50S of the first connection terminal50 a, that is, a length from the recessed portion 51 a disposed at anoutermost end on one end side of the short side 50S to the recessedportion 51 b disposed at an outermost end on the other end side of theshort side 50S is assumed as W. An average diameter of the conductiveparticles 71 is assumed as D1. A width of each recessed portion 51 isassumed as D2. In this case, the angle θ4 may be set to satisfy thefollowing formula 4.Tan θ4≥0.5×(D1+D2)/W  (formula 4)

By disposing the recessed portions 51 and the electrically conductiveparticles 71 so as to satisfy the above-mentioned condition, in acertain row of the electrically conductive particles 71, the pluralityof electrically conductive particles 71 can be prevented from fallinginto the recessed portions 51 respectively and hence, proper pressingcan be applied to the electrically conductive particles 71. Accordingly,the first connection terminal 50 a and the printed circuit board 110 canbe electrically coupled to each other in a more stable manner.

FIG. 9 and FIG. 10 are plan views illustrating the positionalrelationship between the recessed portions 51 and the electricallyconductive particles 71 after the printed circuit board 110 is adheredto the connection terminals 40 a, 40 b by compression bonding via theparticle aligned type anisotropic conductive film 70. FIG. 9 correspondsto FIG. 3, and is a plan view illustrating the positional relationshipbetween the recessed portions 51 and the electrically conductiveparticles 71 after the compression bonding of the printed circuit board110 via the particle aligned type anisotropic conductive film 70. FIG.10 corresponds to FIG. 6, and is a plan view illustrating the positionalrelationship between the recessed portions 51 and the electricallyconductive particles 71 after the compression bonding of the printedcircuit board 110 via the particle aligned type anisotropic conductivefilm 70.

As illustrated in FIG. 9 and FIG. 10, the electrically conductiveparticles 71 may be slightly displaced from the alignment in the firstarrangement direction and the second arrangement direction that are thearrangement directions of the electrically conductive particles 71 atthe time of compression bonding of the printed circuit board 110.

Specifically, the electrically conductive particles 71 in the vicinityof the recessed portions 51 may move and fall into the recessed portions51 at the time of pressing the electrically conductive particles 71 (seeFIG. 26). For example, as illustrated in FIG. 25, in a known terminalportion 40 z, a large number of electrically conductive particles 71 mayfall into recessed portions 51 in a first connection terminal 50 a. FIG.25 is a plan view illustrating the arrangement relationship between therecessed portions 51 of the first connection terminal 50 a and thesecond connection terminal 50 b and the electrically conductiveparticles 71 of the particle aligned type anisotropic conductive film 70in the related art. FIG. 26 is a cross-sectional view illustrating thestructure of the recessed portion 51 in the first connection terminal 50a, and the structure of the recessed portion 51 in the second connectionterminal 50 b. Here, FIG. 25 is a view illustrating an extreme examplefor explicitly describing such a drawback.

Whether or not the recessed portions 51 and the electrically conductiveparticles 71 agree with each other in coordinates is a matter ofprobability. For example, in a case where the arrangement pitch of therecessed portions 51 and the arrangement pitch of the electricallyconductive particles 71 are 10 μm respectively, a size of each recessedportion 51 is 2 μm, and an average diameter of the electricallyconductive particles 71 is 3 μm, the recessed portions 51 and theelectrically conductive particles 71 may overlap with each other withthe probability of approximately 20% with respect to Y coordinates. Withrespect to X coordinates, to take into account the number of severalhundreds of connection terminals, the extension of the particle alignedtype anisotropic conductive film 70 and the like, it should be estimatedthat the recessed portions 51 and the electrically conductive particles71 may overlap with each other at some connection terminals. As aresult, at some connection terminals in the connection terminal portion40 of one liquid crystal panel 100, the coordinates of the recessedportions 51 and the coordinates electrically conductive particles 71 maysubstantially agree with each other with non-ignorable probability.

As illustrated in FIG. 25, when the arrangement direction of therecessed portions 51 and the arrangement direction of the electricallyconductive particles 71 are equal to each other and the arrangementpitch of the recessed portions 51 and the arrangement pitch of theelectrically conductive particles 71 are equal to each other, it isconceivable that the large number of electrically conductive particles71 fall into the recessed portions 51 in the first connection terminal50 a. On the other hand, in the second connection terminal 50 b, it isalso conceivable that most of the electrically conductive particles 71do not fall into the recessed portions 51.

Such a difference may occur at the plurality of connection terminals 50a and 50 b. This is because a state where the recessed portions 51 andthe electrically conductive particles 71 agree with each other inposition at an interval that is the least common multiple of thearrangement pitch of the recessed portions 51 and the arrangement pitchof the electrically conductive particles 71 may occur. When the printedcircuit board 110 is adhered to the connection terminals 50 a and 50 bby compression bonding, the electrically conductive particles 71 of thefirst connection terminal 50 a are pressed insufficiently thus beingminimally collapsed properly, while the electrically conductiveparticles 71 of the second connection terminal 50 b are pressedsufficiently thus being properly and easily collapsed. Accordingly, thefirst connection terminal 50 a is brought into a high electricalresistance state.

In the present embodiment, as illustrated in FIG. 9 and FIG. 10,examples of the electrically conductive particles 71 that are displacedfrom the arrangement in the first arrangement direction or in the secondarrangement direction and fall into the recessed portions 51 when thecompression bonding is performed are indicated by a black dot. Further,when the particle aligned type anisotropic conductive film 70 ismanufactured, there is a certain amount of arrangement failure of theelectrically conductive particles 71, and there exist the electricallyconductive particles 71 that are displaced from an original properarrangement axis and the electrically conductive particles 71 that fallfrom the connection terminals 50 a and 50 b at the time of pressing theelectrically conductive particles 71 and are eventually displaced fromthe original proper arrangement axis. Examples of such electricallyconductive particles 71 are indicated by dotted hatching. Further, amongthe electrically conductive particles 71 disposed between the firstconnection terminal 50 a and the second connection terminal 50 b, thereare some electrically conductive particles 71 that move because ofsoftening of a binder brought about by applying of heat at the time ofpressing the electrically conductive particles 71. Examples of suchelectrically conductive particles 71 are indicated by meshed hatching.

Here, the arrangement direction is a virtual approximate straight linedirection that can be drawn by the plurality of electrically conductiveparticles 71 disposed on the connection terminals 50 a and 50 b andindicated by oblique-line hatching except for the irregular electricallyconductive particles 71. The arrangement direction is not defined by avirtual straight line that can be drawn by the irregular electricallyconductive particles 71. Further, as illustrated in FIG. 10, in thesecond arrangement direction, the widths of the connection terminals 50a and 50 b are narrow and the number of electrically conductiveparticles 71 is insufficient. Accordingly, the second arrangementdirection is assumed as a direction of a virtual approximate straightline that can be drawn by the electrically conductive particles 71except for the irregular electrically conductive particles 71 describedabove when the electrically conductive particles 71 are viewed fromabove across the plurality of connection terminals 50 a and 50 b.

It is needless to say that if one connection terminal 50 a (50 b) has aproper number of electrically conductive particles 71, the direction ofthe virtual approximate straight line that becomes the secondarrangement direction may be obtained from the one connection terminal50 a (50 b). Such a virtual approximate straight line can be recognizedby looking the arrangement of the electrically conductive particles 71at a dummy terminal provided for observing the degree of collapsing ofthe electrically conductive particles 71, for example. If there are aplurality of such dummy terminals, an average direction may be obtainedfrom a plurality of virtual approximate straight lines.

In this manner, since the arrangement direction of the electricallyconductive particles 71 is inclined so as to be different from thearrangement direction of the recessed portions 51, the large number ofelectrically conductive particles 71 are prevented from falling into therecessed portions 51 in the contact structure. Further, by setting theinclination angle of the first arrangement direction to the angle θ1,the angle θ2 or more, it is possible to arrange the electricallyconductive particles 71 to which the proper pressing is applied. Stillfurther, by setting the inclination angle of the second arrangementdirection to the angle θ3, the angle θ4 or more, it is possible todispose the electrically conductive particles 71 to which the properpressing is applied. Accordingly, it is possible to avoid forming theconnection terminal portions 40 a, 40 b that have an extremelydeteriorated electrical characteristic.

Here, as illustrated in FIG. 10, there may be a case where the column ofthe electrically conductive particles 71 at the end portion of theconnection terminal 50 a fall into the column of recessed portions 51.At this time, the width of the external terminals 211 a, 211 b, that is,a width of a copper foil pattern on the printed circuit board 110 is setsuch that the external terminals 211 a, 211 b each include three or morecolumns of the electrically conductive particles 71. More specifically,assuming the average diameter of the electrically conductive particles71 as D1, it is sufficient that the widths of the external terminals 211a, 211 b be set to satisfy the following formula 5.“The width of external terminal of the printed circuit board≥(is equalto or larger than) the arrangement pitch of the electrically conductiveparticles 71 in the X direction×2+D1”  (formula 5).

By setting the width of the external terminal in the printed circuitboard 110 to satisfy the above-mentioned conditions, it is possible toensure at least one column of electrically conductive particles 71 towhich proper pressing can be applied. For example, in FIG. 10, althoughthe external terminal 211 a is ideally aligned so as to include exactlythree rows of electrically conductive particles 71, assuming a casewhere the external terminal 211 a is aligned in a leftwardly displacedmanner by an amount of 0.5 column with respect to the column of theelectrically conductive particles 71, the external terminal 211 aincludes two columns of electrically conductive particles 71. In thiscase, although the electrical connection using only the electricallyconductive particles 71 on the left column entails a risk of connectionfailure because the electrically conductive particles 71 fall into therecessed portions 51, with respect to the electrical connection usingthe electrically conductive particles 71 in the center column, thesecond arrangement direction is inclined with respect to the X directionand hence, the electrically conductive particles 71 do not fall into therecessed portions 51 whereby proper pressing can be applied to theelectrically conductive particles 71. Accordingly, it is possible toavoid forming the connection terminal portion 40 b that has an extremelydeteriorated electrical characteristic.

Although not illustrated in the drawings, when the electricallyconductive particles 71 in the center column fall into the recessedportions 51, the second arrangement direction is inclined with respectto the X direction and hence, the electrically conductive particles 71in the left and right columns do not fall into the recessed portions 51.Accordingly, when the external terminal 211 a is ideally aligned or isaligned in a leftwardly or rightwardly displaced manner by an amount of0.5 column, by setting the width of the external terminal in the printedcircuit board 110 such that the external terminal includes three or morecolumns of the electrically conductive particles 71, the proper pressingcan be applied to the electrically conductive particles 71 on at leasteither one of the left and right columns. Accordingly, it is possible toavoid forming the connection terminal portion 40 b that has an extremelydeteriorated electrical characteristic.

As illustrated in FIG. 11, a projector 1000 as the electronic apparatusof the present embodiment includes a polarized light illumination device1100 disposed along a system optical axis L, two dichroic mirrors 1104,1105 as optical separation elements, three reflection mirrors 1106,1107, and 1108, five relay lenses 1201, 1202, 1203, 1204, and 1205,three transmissive liquid crystal light valves 1210, 1220, and 1230 asthree optical modulation units, a cross dichroic prism 1206 as aphotosynthesis element, and a projection lens 1207.

The polarized light illumination device 1100 generally includes a lampunit 1101 being as a light source including a white light source such asan extra-high pressure mercury lamp or a halogen lamp, an integratorlens 1102, and a polarization conversion element 1103.

The dichroic mirror 1104 reflects the red light (R) of a polarized lightflux exiting from the polarized light illumination device 1100 andtransmits the green light (G) and the blue light (B). The other dichroicmirror 1105 reflects the green light (G) transmitted by the dichroicmirror 1104 and transmits the blue light (B).

The red light (R) reflected by the dichroic mirror 1104 is reflected bythe reflection mirror 1106 and is then incident on the liquid crystallight valve 1210 via the relay lens 1205. The green light (G) reflectedby the dichroic mirror 1105 is incident on the liquid crystal lightvalve 1220 via the relay lens 1204. The blue light (B) transmitted bythe dichroic mirror 1105 is incident on the liquid crystal light valve1230 via a light guide system including the three relay lenses 1201,1202, and 1203 and the two reflection mirrors 1107 and 1108.

The liquid crystal light valves 1210, 1220, and 1230 are each disposedfacing an incident surface of each type of color light of the crossdichroic prism 1206. The color light incident on the liquid crystallight valves 1210, 1220, and 1230 is modulated based on videoinformation (video signal) and exits toward the cross dichroic prism1206.

This prism includes four rectangular prisms bonded together, where oninner surfaces of the prisms, a dielectric multilayer film configured toreflect the red light and a dielectric multilayer film configured toreflect the blue light are formed in a cross shape. The three types ofcolor light are synthesized by these dielectric multilayer films, andlight representing a color image is synthesized. The synthesized lightis projected onto a screen 1300 by the projection lens 1207 being aprojection optical system so that an image is displayed in an enlargedmanner.

The liquid crystal light valve 1210 is a valve to which theabove-mentioned liquid crystal device 500 is applied. The liquid crystaldevice 500 is disposed between a pair of light polarizing elementsdisposed in a crossed-Nicols state at an incident side and an exit sideof the color light with a gap. The same applies to the other liquidcrystal light valves 1220 and 1230.

As the electronic apparatus on which the liquid crystal device 500 ismounted, besides the projector 1000, various electronic apparatus can benamed such as a head-up display (HUD), a head-mounted display (HMD), asmartphone, an electrical view finder (EVF), a mobile mini projector, anelectronic book, a mobile phone, a mobile computer, a digital camera, adigital video camera, a display, onboard equipment, audio equipment, anexposure device, and a lighting equipment.

As has been described above, the liquid crystal device 500 of the firstembodiment includes the liquid crystal panel 100, the particle alignedtype anisotropic conductive film 70 having the electrically conductiveparticles 71 that are regularly arranged in a predetermined arrangementpattern as viewed in plan view, and the printed circuit board 110coupled to the connection terminals 50 a and 50 b of the liquid crystalpanel 100 via the particle aligned type anisotropic conductive film 70.The plurality of recessed portions 51 are formed on the surfaces of theconnection terminals 50 a and 50 b, and the arrangement direction of theelectrically conductive particles 71 and the arrangement direction ofthe recessed portions 51 differ from each other.

According to such a configuration, it is possible to suppress thefalling of the large number of electrically conductive particles 71 intothe recessed portions 51. Accordingly, when the printed circuit board110 is adhered to the connection terminal portions 40 a, 40 b via theparticle aligned type anisotropic conductive film 70 by compressionbonding, the electrically conductive particles 71 to which the properpressing is applied are arranged on the connection terminals 50 a and 50b and hence, it is possible to suppress the lowering of the electricalconnection performance of the connection terminal portions 40 a, 40 b.As a result, it is possible to provide a high-definition andminiaturized liquid crystal device 500.

The electrically conductive particles 71 are arranged in the firstarrangement direction intersecting with the long sides 50L of theconnection terminals 50 a and 50 b and hence, when the recessed portions51 are arranged along the long sides 50L of the connection terminals 50a and 50 b, the arrangement direction of the electrically conductiveparticles 71 and the arrangement direction of the recessed portions 51are different from each other. Accordingly, it is possible to suppressthe falling of the electrically conductive particles 71 into therecessed portions 51.

Further, it is preferable that, assuming a length of an arrangementregion for the recessed portions 51 in each of the connection terminals50 a and 50 b as L, and a width of each recessed portion 51 as D2, theangle θ1 made by an intersection of the direction that the recessedportions 51 are arranged along the long sides 50L of the connectionterminals 50 a and 50 b and the direction that the electricallyconductive particles 71 are arranged in the first arrangement directionbe set to satisfy the following formula 1. Tan θ1≥0.5×D2/L . . .(formula 1)

According to such a configuration, by arranging the recessed portions 51and the electrically conductive particles 71 so as to satisfy theabove-mentioned condition, it is possible to prevent at least oneconductive particle 71 from falling into the recessed portion 51 in acertain column of the electrically conductive particles 71 and hence,proper pressing can be applied to the electrically conductive particle71. Accordingly, the connection terminals 50 a and 50 b and the printedcircuit board 110 can be electrically coupled to each other. Here, it ismore preferable that the angle θ1 be set to satisfy the relationship Tanθ1≥D2/L by taking into account an actual coordinate deviation.

Further, it is preferable that, assuming the length of the arrangementregions for the recessed portions 51 in the connection terminals 50 aand 50 b as L, the average diameter of the electrically conductiveparticles 71 as D1, and the width of each recessed portion 51 as D2, theangle θ2 made by an intersection of the direction that the recessedportions 51 are arranged along the long sides 50L of the connectionterminals 50 a and 50 b and the direction that the electricallyconductive particles 71 are arranged in the first arrangement directionbe set to satisfy the following formula 2. Tan θ2≥0.5×(D1+D2)/L . . .(formula 2)

According to such a configuration, by arranging the recessed portions 51and the electrically conductive particles 71 so as to satisfy theabove-mentioned condition, it is possible to prevent the plurality ofelectrically conductive particles 71 from falling into the recessedportions 51 in a certain column of the electrically conductive particles71 and hence, proper pressing can be applied to the electricallyconductive particles 71. Accordingly, the connection terminals 50 a and50 b and the printed circuit board 110 can be electrically coupled toeach other in a more stable manner.

The electrically conductive particles 71 are arranged in the secondarrangement direction intersecting with the short sides 50S of theconnection terminals 50 a and 50 b and hence, when the recessed portions51 are arranged along the short sides 50S of the connection terminals 50a and 50 b, the arrangement direction of the electrically conductiveparticles 71 and the arrangement direction of the recessed portions 51are different from each other. Accordingly, it is possible to suppressthe falling of a large number of electrically conductive particles 71into the recessed portions 51.

Further, it is preferable that, assuming the width of arrangementregions for the recessed portions 51 in the connection terminals 50 aand 50 b as W, and the width of each recessed portion 51 as D2, theangle θ3 made by intersection of the direction that the recessedportions 51 are arranged along the short sides 50S of the connectionterminals 50 a and 50 b and the direction that the electricallyconductive particles 71 are arranged in the second arrangement directionbe set to satisfy the following formula 3. Tan θ3≥0.5×D2/W . . .(formula 3)

According to such a configuration, by arranging the recessed portions 51and the electrically conductive particles 71 so as to satisfy theabove-mentioned condition, it is possible to prevent at least oneconductive particle 71 from falling into the recessed portion 51 in acertain column of the electrically conductive particles 71 and hence,proper pressing can be applied to the electrically conductive particle71. Accordingly, the connection terminals 50 a and 50 b and the printedcircuit board 110 can be electrically coupled to each other. Here, it ismore preferable that the angle θ3 be set to satisfy the relationship Tanθ3≥D2/W by taking into account an actual coordinate deviation.

Further, it is preferable that, assuming the width of the arrangementregions for the recessed portions 51 in the connection terminals 50 aand 50 b as W, the average diameter of the electrically conductiveparticles 71 as D1, and the width of each recessed portion 51 as D2, theangle θ4 made by intersection of the direction that the recessedportions 51 are arranged along the short sides 50S of the connectionterminals 50 a and 50 b and the direction that the electricallyconductive particles 71 are arranged in the second arrangement directionbe set to satisfy the following formula 4. Tan θ4≥0.5×(D1+D2)/W . . .(formula 4)

According to such a configuration, by arranging the recessed portions 51and the electrically conductive particles 71 so as to satisfy theabove-mentioned condition, it is possible to prevent the plurality ofelectrically conductive particles 71 from falling into the recessedportions 51 in a certain row of the electrically conductive particles 71and hence, proper pressing can be applied to the electrically conductiveparticles 71. Accordingly, the connection terminals 50 a and 50 b andthe printed circuit board 110 can be electrically coupled to each otherin a more stable manner.

When the electrically conductive particles 71 are arranged in the secondarrangement direction intersecting with the short sides 50S of theconnection terminals 50 a and 50 b, with respect to the width of theexternal terminal of the printed circuit board 110, assuming an averagediameter of the electrically conductive particles 71 as D1, it ispreferable that the width of the external terminal of the printedcircuit board 110 be set to satisfy the following formula 5. “The widthof the external terminal of the printed circuit board≥(is equal to orlarger than) the arrangement pitch of the electrically conductiveparticles 71 in the X direction×2+D1” . . . (formula 5).

According to such a configuration, by setting the widths of the externalterminals 211 a, 211 b of the printed circuit board 110 so as to satisfythe above-mentioned conditions, even when the external terminals 211 a,211 b have the alignment deviation in the X direction with respect tothe connection terminals 50 a and 50 b, it is possible to prevent theplurality of electrically conductive particles 71 from falling into therecessed portions 51 and hence, proper pressing can be applied to theelectrically conductive particles 71. Accordingly, the connectionterminals 50 a and 50 b and the printed circuit board 110 can beelectrically coupled to each other in a more stable manner.

By providing the liquid crystal device 500 described above, it ispossible to provide the projector 1000 capable of making the supply ofsignals and voltages stable and improving display quality.

Second Embodiment

As illustrated in FIG. 12, a connection terminal portion 40 c accordingto a second embodiment is formed such that a plurality of recessedportions 51 are arranged in a lattice shape and in a state of beinguniformly aligned along the third arrangement direction and the fourtharrangement direction. Out of the arrangement directions of the recessedportions 51, the third arrangement direction is inclined with respect toan extending direction of long sides 50L of connection terminals 150 aand 150 b, and the fourth arrangement direction is aligned with the Xdirection that is equal to an extending direction of short sides 50S ofthe connection terminals 150 a, 150 b. Further, as viewed in plan view,electrically conductive particles 71 of a particle aligned typeanisotropic conductive film 70 are arranged in a lattice shape and atequal intervals in the X direction and the Y direction. As describedabove, a state where the plurality of electrically conductive particles71 are arranged in a lattice shape and at equal intervals along the Xdirection and the Y direction can be paraphrased as a state where theplurality of electrically conductive particles 71 are arranged in astate of being aligned.

In this manner, the second embodiment differs from the first embodimentin that, in the connection terminal portion 40 c, the arrangementdirection of the recessed portions 51 is inclined with respect to theextending direction of the long side 50L of the first connectionterminal 150 a, and the arrangement direction of the electricallyconductive particles 71 is not inclined with respect to the sides of theconnection terminals 150 a and 150 b. Other configurations of the secondembodiment are substantially equal to the corresponding configurationsof the first embodiment. Accordingly, in the second embodiment, partsthat make the second embodiment different from the first embodiment aredescribed in detail, and the descriptions of other parts identical withthe corresponding parts in the first embodiment are omitted whenappropriate.

As illustrated in FIG. 12, the electrically conductive particles 71 ofthe second embodiment are regularly arranged in parallel to the longside 50L of the first connection terminal 150 a and in a predeterminedarrangement pattern. Further, the electrically conductive particles 71are arranged in a matrix array at predetermined intervals. On the otherhand, the recessed portions 51 of the connection structure are arrangedalong the third arrangement direction intersecting with the long side50L of the first connection terminal 150 a.

Specifically, in the first connection terminal 150 a, a length of thelong side 50L extending along the Y direction is 500 μm, for example,and a length of the short side 50S extending along the X direction is 30μm, for example. The arrangement pitch of the electrically conductiveparticles 71 is 10 μm, for example. For example, the recessed portions51 are arranged in an offset manner by 2 μm in the X direction per everyrow of the recessed portions 51 in the first arrangement direction.

FIG. 12 is a view illustrating a state of the connection terminalportion 40 c after the printed circuit board 110 is adhered to theconnection terminal portion 40 c by compression bonding via the particlealigned type anisotropic conductive film 70. As described above, theelectrically conductive particles 71 that fall into the recessedportions 51 are indicated by a black dot. Further, when the particlealigned type anisotropic conductive film 70 is manufactured, there is acertain amount of arrangement failure of the electrically conductiveparticles 71 where there exist the electrically conductive particles 71that are displaced from an original proper arrangement axis and theelectrically conductive particles 71 that fall from the connectionterminals 150 a and 150 b at the time of pressing the electricallyconductive particles 71 and are eventually displaced from the originalproper arrangement axis. Examples of such electrically conductiveparticles 71 are indicated by dotted hatching. Further, among theelectrically conductive particles 71 disposed between the firstconnection terminal 150 a and the second connection terminal 150 b,there are some electrically conductive particles 71 which move becauseof softening of a binder brought about by applying of heat at the timeof pressing the electrically conductive particles 71. Examples of suchelectrically conductive particles 71 are indicated by meshed hatching.

By arranging the electrically conductive particles 71 and the recessedportions 51 in this manner, four fifths of the entire electricallyconductive particles 71 are prevented from falling into the recessedportions 51. That is, while the arrangement pitch of the electricallyconductive particles 71 is 10 μm, the recessed portions 51 are arrangedin an offset manner by 2 μm in the X direction per every row of therecessed portions 51 in the first arrangement direction and hence, forexample, when the electrically conductive particle 71 falls into therecessed portion 51 in the left column of the first row out of therecessed portions 51 on the first connection terminal 150 a, theelectrically conductive particle 71 that may next fall into the recessedportion 51 in the same manner is the electrically conductive particles71 in the sixth row. Accordingly, the four fifth of the entireelectrically conductive particles 71 are prevented from falling into therecessed portions 51.

As described above, the recessed portions 51 of the connection terminalportion 40 c according to the second embodiment are arranged in thethird arrangement direction intersecting with the long sides 50L of theconnection terminals 150 a and 150 b.

With such a configuration, the recessed portions 51 are arranged in thefirst arrangement direction intersecting with the long sides 50L of theconnection terminals 150 a, 150 b and hence, when the electricallyconductive particles 71 are arranged along the long sides 50L of theconnection terminals 150 a and 150 b, the arrangement direction of therecessed portions 51 and the arrangement direction of the electricallyconductive particles 71 are different from each other. Accordingly, itis possible to suppress the falling of a large number of electricallyconductive particles 71 into the recessed portions 51.

Third Embodiment

FIG. 13 and FIG. 14 are views illustrating configurations of connectionterminal portions 40 d and 40 e according to a third embodiment. In thethird embodiment, electrically conductive particles 71 of a particlealigned type anisotropic conductive film 70 are arranged in a latticeshape and in a state of being uniformly aligned along the X directionand the Y direction as viewed in plan view. Further, recessed portions51 of connection terminals 151 a, 151 b, 152 a, and 152 b are alsoarranged in a lattice shape and in a state of being uniformly alignedalong the X direction and the Y direction as viewed in plan view.

In the third embodiment, an arrangement pitch of the electricallyconductive particles 71 and an arrangement pitch of the recessedportions 51 are different from each other. Specifically, in the Ydirection, the arrangement pitch of the recessed portions 51 of theconnection terminals 151 a, 151 b, 152 a, and 152 b along the Ydirection is larger than the arrangement pitch of the electricallyconductive particles 71 of the particle aligned type anisotropicconductive film 70 along the Y direction (see FIG. 13) or smaller thanthe arrangement pitch of the electrically conductive particles 71 alongthe Y direction (see FIG. 14). Other configurations of the thirdembodiment are substantially equal to the corresponding configurationsof the first embodiment. Accordingly, in the third embodiment, partsthat make the third embodiment different from the first embodiment aredescribed in detail, and the descriptions of other parts identical withthe corresponding parts in the first embodiment are omitted whenappropriate.

As illustrated in FIG. 13, the electrically conductive particles 71 ofthe connection terminal portion 40 d according to the third embodimentare arranged in a matrix array so as to keep a predetermined intervalbetween the electrically conductive particles 71 adjacent to each other.On the other hand, the recessed portions 51 are arranged in a directionalong a long side 50L of the first connection terminal 151 a at a firstarrangement pitch A that is larger than the arrangement pitch of theelectrically conductive particles 71.

For example, assume that the arrangement pitch of the electricallyconductive particles 71 is 10 μm, and the arrangement pitch of therecessed portions 51 is 50χ4 μm. In this case, the electricallyconductive particles 71 may overlap with the recessed portions 51 atevery five other electrically conductive particles 71. In other words,out of five electrically conductive particles 71, four electricallyconductive particles 71 do not fall into the recessed portions 51.

In this manner, by setting the arrangement pitch of the recessedportions 51 in the direction of the long side 50L of the firstconnection terminal 151 a larger than the arrangement pitch of theelectrically conductive particles 71, according to the presentembodiment, in each column of the electrically conductive particles 71,approximately 80% of electrically conductive particles 71 can beprevented from falling into the recessed portions 51. Accordingly, it ispossible to prevent the large number of electrically conductiveparticles 71 from falling into the recessed portions 51 and hence,proper pressing can be applied to the large number of electricallyconductive particles 71. That is, it is possible to avoid forming theconnection terminal portion 40 d that has an extremely deterioratedelectrical characteristic.

Further, “setting the arrangement pitch of the recessed portions 51larger than the arrangement pitch of the electrically conductiveparticles 71” means that the number of recessed portions 51 per unitarea is set smaller than the number of electrically conductive particles71 per unit area in the connection terminal 151 a (151 b). Accordingly,since there are electrically conductive particles 71 that do not fallinto the recessed portions 51, proper pressing can be applied to suchelectrically conductive particles 71.

As illustrated in FIG. 14, in the same manner as the arrangement of theelectrically conductive particles 71 illustrated in FIG. 13, theelectrically conductive particles 71 of the connection terminal portion40 e according to the third embodiment are arranged in a matrix array soas to keep a predetermined interval between the electrically conductiveparticles 71 adjacent to each other. On the other hand, the recessedportions 51 are arranged in the direction (Y direction) along the longside 50L of the first connection terminal 152 a at a second arrangementpitch B that is smaller than the arrangement pitch of the electricallyconductive particles 71.

For example, assume that the arrangement pitch of the electricallyconductive particles 71 is 10 μm, and the arrangement pitch of therecessed portions 51 is 40χ5 μm. In this case, the electricallyconductive particles 71 may overlap with the recessed portions 51 atevery four other electrically conductive particles 71. In other words,out of four electrically conductive particles 71, three electricallyconductive particles 71 do not fall into the recessed portions 51.

In this manner, by setting the arrangement pitch of the recessedportions 51 in the direction of the long side 50L of the firstconnection terminal 152 a smaller than the arrangement pitch of theelectrically conductive particles 71, in the present embodiment,approximately 70% of electrically conductive particles 71 can beprevented from falling into the recessed portions 51 in each column ofthe electrically conductive particles 71. Accordingly, it is possible toprevent the large number of electrically conductive particles 71 fromfalling into the recessed portions 51 and hence, proper pressing can beapplied to the large number of electrically conductive particles 71.That is, it is possible to avoid forming the connection terminal portion40 e that has an extremely deteriorated electrical characteristic.

In this embodiment, as described above, the recessed portions 51 arearranged at the first arrangement pitch A that is larger than thearrangement pitch of the electrically conductive particles 71 or arearranged at the second arrangement pitch B that is smaller than thearrangement pitch of the electrically conductive particles 71 in the Ydirection. However, the present disclosure is not limited to suchconfigurations, and the recessed portions 51 may be arranged at thefirst arrangement pitch A that is larger than the arrangement pitch ofthe electrically conductive particles 71 or may be arranged at thesecond arrangement pitch B that is smaller than the arrangement pitch ofthe electrically conductive particles 71 in the X direction.

As described above, the recessed portions 51 of the connection terminalportions 40 d, 40 e according to the third embodiment are preferablyarranged so as to include at least one of an arrangement that therecessed portions 51 are arranged at the first arrangement pitch A thatis larger than the arrangement pitch of the electrically conductiveparticles 71 and an arrangement that the recessed portions 51 arearranged in the second arrangement pitch B that is smaller than thearrangement pitch of the electrically conductive particles 71.

According to such a configuration, the arrangement pitch of the recessedportions 51 and the arrangement pitch of the electrically conductiveparticles 71 are different from each other and hence, it is possible tosuppress the falling of the large number of electrically conductiveparticles 71 into the recessed portions 51.

MODIFICATION EXAMPLE

The mode for carrying out the present disclosure is not limited to theconfigurations of the first to third embodiments described above, andmay also be configured as follows. FIG. 15 to FIG. 24 are plan viewsillustrating configurations of terminal portions 40 f, 40 g, 40 h, 40 i,40 j, 40 k, 40 l, 40 m, 40 n, and 40 p of modification examples.

First Modified Example

In a first modification example illustrated in FIG. 15, electricallyconductive particles 71 of a particle aligned type anisotropicconductive film 70 are arranged in a lattice shape and in a state ofbeing uniformly aligned along a first arrangement direction and a secondarrangement direction as viewed in plan view. In FIG. 15, the firstarrangement direction and the second arrangement direction are inclinedwith respect to an extending direction (Y direction) of long sides 50Lof connection terminals 50 a and 50 b and an extending direction (Xdirection) of short sides 50S of the connection terminals 50 a and 50 brespectively. In FIG. 15, recessed portions 51 of the connectionterminals 50 a and 50 b are arranged in a lattice shape and in a stateof being uniformly aligned along the X direction and the Y direction asviewed in plan view.

Specifically, as illustrated in FIG. 15, a terminal portion 40 f of themodification example is formed such that the arrangement of theelectrically conductive particles 71 includes both the arrangement inthe first arrangement direction that intersects with the long side 50Lof the first connection terminal 50 a and the arrangement in the secondarrangement direction that intersects with the short side 50S of thefirst connection terminal 50 a. FIG. 15 illustrates a state of the firstconnection terminal 50 a, the second connection terminal 50 b, theelectrically conductive particles 71, and external terminals 111 a and111 b of a printed circuit board 110 in the terminal portion 40 f of themodification example after the printed circuit board 110 is adhered tothe terminal portion 40 f by compression bonding via the particlealigned type anisotropic conductive film 70. According to the firstembodiment, it is preferable that an inclination angle of the firstarrangement direction be set to equal to or more than an angle θ2 and aninclination angle of the second arrangement direction be set to equal toor more than an angle θ4.

Second Modified Example

In a second modification example illustrated in FIG. 16, electricallyconductive particles 71 of a particle aligned type anisotropicconductive film 70 are arranged along a first arrangement direction, asecond arrangement direction, and a fifth arrangement direction thatintersects with the first arrangement direction and the secondarrangement direction in a state of being aligned at positions where therespective arrangement directions intersect with each other as viewed inplan view. In FIG. 16, the first arrangement direction and the secondarrangement direction are respectively inclined with respect to anextending direction (Y direction) of long sides 50L of connectionterminals 50 a and 50 b and an extending direction (X direction) ofshort sides 50S of the connection terminals 50 a and 50 b in the samemanner as the configuration illustrated in FIG. 15.

As illustrated in FIG. 16, recessed portions 51 of the connectionterminals 50 a and 50 b are arranged in a lattice shape and in a stateof being uniformly aligned along the X direction and the Y direction asviewed in plan view. FIG. 16 illustrates a state of the first connectionterminal 50 a, the second connection terminal 50 b, the electricallyconductive particles 71, and external terminals 111 a, 111 b of aprinted circuit board 110 in a terminal portion 40 g of the secondmodification example after the printed circuit board 110 is adhered tothe terminal portion 40 g by compression bonding via the particlealigned type anisotropic conductive film 70.

According to the terminal portion 40 g of the second modificationexample, the electrically conductive particles 71 are arranged so as toform a hexagonal shape. For example, when the electrically conductiveparticles 71 are arranged so as to form a regular hexagonal shape, thefirst arrangement direction, the second alignment direction, and thefifth alignment direction differ from each other by 60 degrees. Here,with respect to the first arrangement direction, the second arrangementdirection, and the fifth arrangement direction, it is sufficient that atleast one of the arrangement directions satisfies the inclinationcondition in the above-mentioned first embodiment.

In the terminal portion 40 g of the second modification example, theelectrically conductive particles 71 are arranged in the firstarrangement direction, the second arrangement direction, and the thirdarrangement direction that intersect with the long sides 50L and theshort sides 50S of the connection terminals 50 a and 50 b and hence,when the recessed portions 51 are arranged along the long sides 50L andthe short sides 50S of the connection terminals 50 a and 50 b, thearrangement direction of the electrically conductive particles 71 andthe arrangement direction of the recessed portions 51 are different fromeach other. Accordingly, it is possible to suppress the falling of alarge number of electrically conductive particles 71 into the recessedportions 51.

Third Modified Example

In a third modification example illustrated in FIG. 17, electricallyconductive particles 71 of a particle aligned type anisotropicconductive film 70 are arranged in a lattice shape and in a state ofbeing uniformly aligned along the X direction and the Y direction asviewed in plan view. In FIG. 17, recessed portions 51 of connectionterminals 153 a and 153 b are arranged in a lattice shape and in a stateof being uniformly aligned along a third alignment direction and afourth arrangement direction as viewed in plan view. Here, the thirdarrangement direction is the same direction as the Y direction, and thefourth arrangement direction is a direction that intersects with shortsides 50S of the connection terminals 153 a and 153 b.

Specifically, the recessed portions 51 are arranged in an offset mannerby 2 μm in the Y direction per every column of the recessed portions 51in the fourth arrangement direction. FIG. 17 illustrates a state of thefirst connection terminal 153 a, the second connection terminal 153 b,the electrically conductive particles 71, and external terminals 211 a,211 b of a printed circuit board 110 in a connection terminal portion 40h of the modification example after the printed circuit board 110 isadhered to the connection terminal portion 40 h by compression bondingvia the particle aligned type anisotropic conductive film 70.

With such a configuration, with respect to two columns of the recessedportions 51 adjacent to each other, the electrically conductiveparticles 71 are prevented from falling into the recessed portions 51 ineither one of two columns. Accordingly, it is preferable that a width ofa copper foil pattern that forms the external terminals 211 a, 211 b ofthe printed circuit board 110 be set to include three columns of theelectrically conductive particles 71.

Further, the arrangement direction of the recessed portions 51 ischanged and hence, the probability that the electrically conductiveparticles 71 fall into the recessed portions 51 can be reducedcorresponding to the various arrangement directions of the electricallyconductive particles 71 of the particle aligned type anisotropicconductive film 70. Accordingly, options in selecting a manufacturer ofthe particle aligned type anisotropic conductive films 70 to be used canbe increased. The first arrangement direction of the recessed portions51 in the connection terminal portion 40 c according to the secondembodiment and the second arrangement direction of the recessed portions51 in the connection terminal portion 40 h according to the modificationexample may be used in combination.

As described above, the recessed portions 51 of the connection terminalportion 40 h of the third modification example are arranged in thefourth arrangement direction intersecting with the short sides 50S ofthe connection terminals 153 a, 153 b and hence, when the electricallyconductive particles 71 are arranged along the short sides 50S of theconnection terminals 153 a and 153 b, the arrangement direction of therecessed portions 51 and the arrangement direction of the electricallyconductive particles 71 are different from each other. Accordingly, itis possible to suppress the falling of the electrically conductiveparticles 71 into the recessed portions 51.

Further, in the connection terminal portions 40 d, 40 e according to thethird embodiment, with respect to the arrangement pitch of the recessedportions 51 of the first connection terminal 151 a, the recessedportions 51 are arranged at the first arrangement pitch A that is largerthan the arrangement pitch of the electrically conductive particles 71of the particle aligned type anisotropic conductive film 70 or arearranged at the second arrangement pitch B that is smaller than thearrangement pitch of the electrically conductive particles 71 in the Ydirection. However, the arrangement of the recessed portions 51 is notlimited to such a configuration, and the recessed portions 51 may bearranged as illustrated in FIG. 18 and FIG. 19.

Fourth Modification Example

In the fourth modification example illustrated in FIG. 18, recessedportions 51 are arranged such that an arrangement where the recessedportions 51 are arranged at a first arrangement pitch A that is largerthan an arrangement pitch of electrically conductive particles 71 and anarrangement where the recessed portions 51 are arranged at a secondarrangement pitch B that is smaller than the arrangement pitch of theelectrically conductive particles 71 are repeated in the Y direction. Inthe fourth modification example illustrated in FIG. 19, the recessedportions 51 are arranged such that an arrangement where the recessedportions 51 are arranged at the first arrangement pitch A that is largerthan the arrangement pitch of the electrically conductive particles 71and an arrangement where the recessed portions 51 are arranged at thesecond arrangement pitch B that is smaller than the arrangement pitch ofthe electrically conductive particles 71 are repeated in the X directionand in the Y direction.

According to this configuration, the two types of arrangement pitchesthat differ from each other are repeated with respect to the arrangementpitch of the electrically conductive particles 71 and hence, in aterminal portion 40 i illustrated in FIG. 18, it is possible to preventat least 50% of electrically conductive particles 71 from falling intothe recessed portions 51 in each column of the electrically conductiveparticles 71. The large number of electrically conductive particles 71do not fall into the recessed portions 51 and hence, proper pressing canbe applied to the large number of electrically conductive particles 71.In a terminal portion 40 j illustrated in FIG. 19, three out of four,that is, approximately 75% of electrically conductive particles 71 canbe prevented from falling into the recessed portions 51.

Fifth Modification Example

Additionally, an arrangement of the recessed portions 51 is not limitedto the arrangements described in the second embodiment, the thirdembodiment and the above-mentioned modification examples, and therecessed portions 51 may be arranged at random as in the case of thefifth modification example illustrated in FIG. 20 and FIG. 21. The fifthmodification example illustrated in FIG. 20 shows a configuration wherea virtual frame is set for each electrically conductive particle 71, anda recessed portion 51 is arranged at random within a range of the frame.The arrangement of the recessed portions 51 of a first connectionterminals 156 a and the arrangement of recessed portions 51 of a secondconnection terminals 156 b are set equal to each other.

The electrically conductive particles 71 are regularly arranged in amatrix array in parallel to a long side 50L of the first connectionterminal 156 a and in a predetermined arrangement pattern. The virtualframe has a square shape with a side of 9 μm, for example. Anarrangement pitch of the virtual frames is 10 μm, for example. Therecessed portion 51 has a square shape with a side of 2 μm, for example.The positions of the recessed portions 51 are moved by changingcoordinates of the recessed portions 51 using random numbers. Withrespect to the size of the virtual frame, a length of one side of thesquare shape is 9 μm and hence, assuming center coordinates of thevirtual frame as an origin, the recessed portion 51 can move within arange of ±3.5 μm in XY coordinates. While the arrangement pitch of thevirtual frame is 10 μm, the virtual frame is formed in a square shapewith a side of 9 μm and hence, at least 1 μm is guaranteed as a spacebetween the recessed portions 51 included in the adjacent virtual framesrespectively. Such setting of the sizes is an example of treatment forobserving the rules on spaces of the connection structure where therecessed portions 51 are formed.

Accordingly, by determining the X coordinate correction value (=−3.5 μmto +3.5 μm) and the Y coordinate correction value (=−3.5 μm to +3.5 μm)at random, the random arrangement of the recessed portions 51 can berealized. When the coordinate correction value is set to a value equalto or larger than a radius that is a half of an average diameter of theelectrically conductive particles 71, the probability that falling ofthe electrically conductive particles 71 into the recessed portions 51can be prevented is increased. For example, when a diameter of theelectrically conductive particle 71 is set to 3 μm, the recessed portion51 can optionally take 5 positions in the X coordinate and canoptionally take 5 positions in the Y coordinate and hence, the recessedportion 51 can be arranged in 25 patterns in total within the virtualframe.

In the fifth modification example illustrated in FIG. 21 the recessedportions 51 are arranged at random within the virtual frame, and thearrangement of the recessed portions 51 on a first connection terminal157 a and the arrangement of the recessed portions 51 on a secondconnection terminal 157 b are made different from each other. That is,the different connection terminals 157 a, 157 b adopt the differentrandom arrangements in arranging the recessed portions 51. By disposingthe recessed portions 51 in this manner, the probability that thealigned electrically conductive particles 71 fall into the recessedportions 51 is largely reduced. Further, since the recessed portions 51are arranged at random by setting the virtual frames, the number ofconnection structures per unit area is not changed. Accordingly, theelectrical connection resistances of the respective connection terminals157 a and 157 b can be made uniform to a degree that the difference inthe electrical connection resistance can be made substantiallyignorable.

By configuring the terminal portions 40 k, 40 l as described above, thearrangement of the recessed portions 51 can be randomized and hence, theprobability that the aligned electrically conductive particles 71 fallinto the recessed portions 51 is largely reduced. Such a configurationis effective regardless of the arrangement method of the electricallyconductive particles 71 and hence, the electro-optical device canflexibly cope with the various arrangements of the electricallyconductive particles 71 of the particle aligned type anisotropicconductive film 70.

Sixth Modification Example

The arrangement of the recessed portions 51 is not limited to theabove-described embodiments and the above-mentioned modificationexamples, and the recessed portions 51 may be arranged as described inthe sixth modification example illustrated in FIG. 22 to FIG. 24. FIG.22 to FIG. 24 are plan views illustrating configurations of connectionterminal portions 40 m, 40 n, and 40 p according to the sixthmodification example. In the connection terminal portion 40 millustrated in FIG. 22, recessed portions 51 are arranged along an outershape of a first connection terminal 158 a. An arrangement pitch of therecessed portion 51 is 5 μm, for example. Electrically conductiveparticles 71 are regularly arranged in a matrix array in parallel to along side 50L of the first connection terminal 158 a and in apredetermined arrangement pattern. An arrangement pitch of theelectrically conductive particles 71 is 10 μm, for example.

With such a configuration, in the worst case, the electricallyconductive particles 71 fall into the recessed portions 51 arrangedalong the outer shape of the first connection terminal 158 a. However,the recessed portion 51 is not arranged at the center portion of thefirst connection terminal 158 a and hence, the electrically conductiveparticles 71 remain at the center portion, and proper pressing isapplied to the remaining electrically conductive particles 71 thusensuring the electrical connection between the first connection terminal158 a and a copper foil pattern forming external terminals 111 a, 111 bof a printed circuit board 110. Further, the recessed portions 51 arearranged along the outer shape of the first connection terminal 158 aand hence, in a case of using the first connection terminal 158 a havinga narrow width, even when an electrode layer forming an uppermost layerof the first connection terminal 158 a is made of a material having arelatively high sheet resistance such as ITO, for example, a distancefrom the center portion of the first connection terminal 158 a to eachof the recessed portions 51 (connection structures) arranged along thelong side 50L is short and hence, the first connection terminal 158 acan be connected to a wiring layer disposed below the first connectionterminal 158 a with low resistance.

The connection terminal portion 40 n illustrated in FIG. 23 differs fromthe connection terminal portion 40 m illustrated in FIG. 22 in that anarrangement of the electrically conductive particles 71 includes boththe arrangement of the electrically conductive particles 71 in a firstarrangement direction intersecting with a long side 50L of a firstconnection terminal 158 a and the arrangement of the electricallyconductive particles 71 in a second arrangement direction intersectingwith a short side 50S of the first connection terminal 158 a. Accordingto this configuration, when the electrically conductive particles 71 areviewed in a projection view in a direction of the long side 50L of thefirst connection terminal 158 a, the electrically conductive particles71 adjacent to each other appear in an overlapping manner with eachother. Accordingly, such a configuration acts as if there is a virtualelectrical connection region diagonally traversing the first connectionterminal 158 a. Further, in the first connection terminal 158 a and thesecond connection terminal 158 b, a change in quantity or number ofelectrically conductive particles 71 existing in a region disposed at acenter portion of the terminal where the recessed portions 51 are notformed can be reduced and hence, the first connection terminal 158 a andthe second connection terminal 158 b can have the similar electricalconnection performances.

The terminal portion 40 p illustrated in FIG. 24 has a configurationwhere an arrangement of electrically conductive particles 71 includesboth an arrangement in a first arrangement direction and an arrangementin a second arrangement direction as illustrated in FIG. 23 and, inaddition, includes an arrangement in a third arrangement directionintersecting with the first arrangement direction and the secondarrangement direction.

In the modification examples illustrated in FIG. 22 to FIG. 24, therecessed portion 51 is not arranged at the center portion of theconnection terminal 158 a (158 b). However, the recessed portion 51(indicated by a broken line) may be arranged near the center of theconnection terminal 158 a such that the number of the recessed portions51 (indicated by a broken line) is less than the number (density) ofrecessed portions 51 arranged along the outer shape of the connectionterminal 158 a. For example, in the modification example of FIG. 24,although the recessed portions 51 arranged along the outer shape of theconnection terminal 158 a have an arrangement pitch of 5 μm, a pluralityof recessed portions 51 may be arranged at the center portion of theconnection terminal 158 a in the Y direction at an arrangement pitch of20 μm to 100 μm, for example. Such arrangement may be randomized. In anycase, in the connection terminal 158 a (158 b), the number (density) ofthe recessed portions 51 arranged at the center portion is less than thenumber (density) of the recessed portions 51 arranged at the peripheralportion. Even with such a configuration, the probability that theelectrically conductive particles 71 at the center portion fall into therecessed portions 51 can be reduced and hence, proper pressing can beapplied to the large number of electrically conductive particles 71 thusensuring the electrical connection between the connection terminal 158 a(158 b) and the copper foil pattern forming the external terminal 111 a(111 b) of the printed circuit board 110. The fact that the recessedportion 51 is arranged at the center portion is a result of adding theconnection structure and hence, the electrical connection between theelectrode layer forming the uppermost layer and the wiring layer belowthe electrode layer is strengthened.

In the embodiments, although the description has been made with respectto the configuration that the printed circuit board 110 is mounted onthe connection terminals 50 a and 50 b formed on the element substrate10 that forms the liquid crystal panel 100, the present disclosure isnot limited to such a configuration. The present disclosure may also beapplicable to a configuration of a Chip On Glass (COG) where a drivingintegrated circuit is mounted on connection terminals 50 a and 50 bformed on the element substrate 10.

Further, the electro-optical device to which the present disclosure isapplied is not limited to the liquid crystal device 500 described above,for example, and the present disclosure may also be applicable to anorganic EL device, a plasma display, an electronic paper (EPD) or thelike.

What is claimed is:
 1. An electro-optical device comprising: anelectro-optical panel; and an anisotropic conductive film having aplurality of electrically conducive particles that are arranged along afirst direction and a second direction intersecting with the firstdirection as viewed in plan view, wherein the electro-optical panel hasa terminal that is coupled to a printed circuit board via theanisotropic conductive film, the terminal has a plurality of recessedportions that are arranged along a third direction and a fourthdirection intersecting with the third direction, at least one of thefirst direction and the second direction along which the electricallyconductive particles are arranged is different in arrangement directionfrom both the third direction and the fourth direction along which therecessed portions are arranged.
 2. The electro-optical device accordingto claim 1, wherein the first direction is a direction intersecting withan extending direction of a long side of the terminal, the seconddirection is a direction along an extending direction of a short side ofthe terminal, the third direction is a direction along an extendingdirection of the long side of the terminal, and the fourth direction isa direction along the extending direction of the short side of theterminal.
 3. The electro-optical device according to claim 1, whereinthe first direction is a direction along an extending direction of along side of the terminal, the second direction is a directionintersecting with an extending direction of a short side of theterminal, the third direction is a direction along the extendingdirection of the long side of the terminal, and the fourth direction isa direction along the extending direction of the short side of theterminal.
 4. The electro-optical device according to claim 1, whereinthe first direction is a direction along an extending direction of along side of the terminal, the second direction is a direction along anextending direction of a short side of the terminal, the third directionis a direction intersecting with the extending direction of the longside of the terminal, and the fourth direction is a direction along theextending direction of the short side of the terminal.
 5. Theelectro-optical device according to claim 1, wherein the first directionis a direction along an extending direction of a long side of theterminal, the second direction is a direction along an extendingdirection of a short side of the terminal, the third direction is adirection along the extending direction of the long side of theterminal, and the fourth direction is a direction intersecting with theextending direction of the short side of the terminal.
 6. Theelectro-optical device according to claim 2, wherein an angle θ1 formedby the third direction and the first direction intersecting each othersatisfies a following formula 1Tan θ1≥0.5×D2/L  (formula 1) where a length between recessed portionsarranged at both ends of the long side of the terminal out of therecessed portions arranged along the third direction is L and a width ofthe terminal is D2.
 7. The electro-optical device according to claim 2,wherein an angle θ2 formed by the third direction and the firstdirection intersecting with each other satisfies a following formula 2Tan θ2≥0.5×(D1+D2)/L  (formula 2) where a length between recessedportions arranged at both ends of the long side of the terminal out ofthe recessed portions arranged along the third direction is L, anaverage diameter of the electrically conductive particles is D1, and awidth of the recessed portion is D2.
 8. The electro-optical deviceaccording to claim 3, wherein an angle θ3 formed by the fourth directionand the second direction satisfies a following formula 3Tan θ3≥0.5×D2/W  (formula 3) where a length between recessed portionsarranged at both ends of the short side of the terminal out of therecessed portions arranged along the fourth direction is W and a widthof the recessed portion is D2.
 9. The electro-optical device accordingto claim 3, wherein an angle θ4 formed by the fourth direction and thesecond direction satisfies a following formula 4Tan θ4≥0.5×(D1+D2)/W  (formula 4) where a length between recessedportions arranged at both ends of the short side of the terminal out ofthe recessed portions arranged along the fourth direction is W, anaverage diameter of the electrically conductive particles is D1, a widthof the recessed portion is D2.
 10. The electro-optical device accordingto claim 1, wherein the electrically conductive particles includeelectrically conductive particles arranged in a fifth directionintersecting with the first direction and the second direction.
 11. Theelectro-optical device according to claim 1, wherein the recessedportions are arranged at a pitch including at least one of a firstarrangement pitch that is larger than an arrangement pitch of theelectrically conductive particles and a second arrangement pitch that issmaller than the arrangement pitch of the electrically conductiveparticles.
 12. An electronic apparatus, comprising: the electro-opticaldevice according to claim 1.